1. Field of Disclosure
The present disclosure relates generally to improvements in reading bar code symbols in point-of-sale (POS) environments in ways which increase flexibility and POS throughput.
2. Brief Description of the State of Knowledge in the Art
The use of bar code symbols for product and article identification is well known in the art. Presently, various types of bar code symbol scanners have been developed for reading bar code symbols at retail points of sale (POS).
In demanding retail environments, such as supermarkets and high-volume department stores, where high check-out throughput is critical to achieving store profitability and customer satisfaction, it is common to use laser scanning bar code reading systems having both bottom and side-scanning windows to enable highly aggressive scanner performance. In such systems, the cashier need only drag a bar coded product past these scanning windows for the bar code thereon to be automatically read with minimal assistance from the cashier or checkout personal. Such dual scanning window systems are typically referred to as “bi-optical” laser scanning systems as such systems employ two sets of optics disposed behind the bottom and side-scanning windows thereof. Examples of polygon-based bi-optical laser scanning systems are disclosed in U.S. Pat. Nos. 4,229,588, 4,652,732 and 6,814,292; each incorporated herein by reference in its entirety. Commercial examples of bi-optical laser scanners include: the PSC 8500-6-sided laser based scanning by PSC Inc.; PSC 8100/8200, 5-sided laser based scanning by PSC Inc.; the NCR 7876-6-sided laser based scanning by NCR; the NCR7872, 5-sided laser based scanning by NCR; and the MS232x Stratos® H, and MS2122 Stratos® E 6 sided laser based scanning systems by Metrologic Instruments, Inc., and the MS2200 Stratos® S 5-sided laser based scanning system by Metrologic Instruments, Inc.
With the increasing appearance of 2D bar code symbologies in retail store environments (e.g. reading driver's licenses for credit approval, age proofing etc), there is a growing need to support digital-imaging based bar code reading—at point of sale (POS) stations.
U.S. Pat. No. 7,540,424 B2 and U.S. Publication No. 2008/0283611 A1, assigned to Metrologic Instruments, Inc, describes high-performance digital imaging-based POS bar code symbol readers employing planar illumination and digital linear imaging techniques, as well as area illumination and imaging techniques.
U.S. Pat. Nos. 7,137,555; 7,191,947; 7,246,747; 7,527,203 and 6,974,083 disclose hybrid laser scanning and digital imaging systems, in which a digital imager is integrated within a POS-based laser scanning bar code symbol reading system. In such system designs, the digital imager helps the operator read poor quality codes, and also enables the hybrid system to read 2D symbologies. The use of digital imaging at the POS is capable of capturing virtually every dimension and perspective of a bar code symbol, and is capable of making more educated decisions on how to process the symbology.
However, when using digital imaging, throughput speed at the POS is typically much less than when using a bi-optical laser scanning system, due to expected frame rates and image processing time. With digital imaging, issues may arise when objects are moved too quickly through the field of view (FOV) of the imager, producing digital images that are blurred and sometimes hard to read. Also, while the techniques disclosed in U.S. Pat. No. 7,540,424 and US Patent Application Publication No. 2010/0302420 can reduce the effects of illumination on human observers during digital imaging at POS checkout stations, there is still a need for improvement in this regard when the continuous digital video imaging mode is preferred, without sacrificing throughput and/or performance.
Thus, despite the many improvements in both laser scanning and digital imaging based bar code symbol readers over the years, there is still a great need in the art for an improved hybrid-type bar code symbol reading system which is capable of high-performance and robust operations in demanding POS scanning environments, while avoiding the shortcomings and drawbacks of prior art systems and methodologies.